This invention pertains generally to power combiners for solid state devices, and particularly to a power combiner with concentric rings of coaxial diode oscillators.
It is known in the art (see U.S. Pat. No. 3,931,587) that a microwave power source may be formed by providing a circularly cylindrical cavity wherein outputs of a plurality of coaxial diode oscillators may be combined in a proper phasic relationship. In the source illustrated in the just-cited patent, diode oscillators are symmetrically disposed on the periphery of a circularly cylindrical cavity dimensioned to operate in the TM.sub.010 mode. The number of coaxial diode oscillators that may be so disposed is limited by the length of such periphery, with the result that the amount of microwave power out of such a combiner is similarly limited. It is also known in the art (see U.S. Pat. No. 4,189,684) that if the length of the periphery of a cylindrical cavity were to be increased so that the TM.sub.020 mode could be supported in such a cavity, the power out of a greater number of coaxial diode oscillators may be combined to increase microwave power out of a microwave power source. However, to avoid the occurrence of unwanted modes with attendant instability, it is necessary to provide mode suppressors. Any known type of mode suppressor absorbs microwave power that otherwise could contribute to the power out of the microwave power source.